1. Field of the Invention
The present invention relates to telecommunications networks and in particular to the control of data relating thereto.
2. Related Art
Modern communications networks provide great flexibility to customers. For example, telephone customers have the ability to control the diversion of telephone calls from their own telephone number to any other telephone number on the network.
Similarly, network operators provide flexible services to business customers. Such services as "0800" or "freefone" enable customers to dial a call without being charged (a form of automatic reverse charge calling). The caller is connected by the network to a telephone, the network number of which is derived from the 0800 number.
One procedure for these kinds of service has been to establish a call across the physical network from the calling customer to a network service point (eg to the main switching unit nearest the called customer in the case of call diversion) and then to establish a call across the physical network from the network service point to the diverted network number.
Such procedures waste network resources particularly if two long distance call connections are required to effect a "local" call. This is particularly so if, for example, calls to service numbers are connected in dependence upon the calling customer location.
As network switching speeds improve and the apparent near-instantaneous connection between any two network numbers becomes possible, it is more common for the switching unit to which the calling customer is connected to apply to another point in the network for an actual network number before effecting a call connection. Thus, in the case of call diversion, data-interchange between the originating switching unit and the destination switching unit causes the diversion information to be returned to the originating unit which then establishes a call to the designated network number.
This function becomes more important where number portability or so-called personal numbering is required. Since there is no relationship between any physical connection point in the network and the called number, practically every call requires a translation in the same way as 0800 and similar services currently require.
With translated number services, a service control point provides the destination network number to the originating switching unit. The provided number may be dependent on day of week, time of day or other factors at the called customers discretion. The data held in the service control point is usually under the control of the network operator who effects changes at the request of the customer. However, it may be desirable to allow the customer to effect changes to some of this data.
Similarly, with personal numbering a service control point holds data in respect of one or more nominal physical network codes or numbers. Customers may have the ability to set up time of day/day of week translations and to modify such data from time to time. Alternatively or additionally, the "intelligence" associated with the switching unit may be responsive to customer location data. Finally, the network operator may be required to modify customer related data to restrict or allow certain services to or from specific customers.
As the service provided to and/or selected by the customer now depends upon data held in respect of that customer, as may variations in charges for customer service, it is essential that any data modification carried out by the network operator does not result in unwanted changes to data stored by other authorized persons.
Maintaining a full record of every customer's currently absolute status at each potential service amendment point becomes impractical as the number of such points in the network and the level of flexibility in the network increase.